Proceedings of MATSUS Spring 2024 Conference (MATSUS24)
DOI: https://doi.org/10.29363/nanoge.matsus.2024.143
Publication date: 18th December 2023
Over the last ten years, the role of hybrid metal halide perovskites has received significant attention as suitable materials for various electronic applications. Indeed, their outstanding optoelectronic properties, such as high-power conversion efficiency, tunable bandgap, and high absorption coefficient, make them suited for several applications in different devices as photovoltaic cells, photodetectors, light emitting diodes, and sensors [2]. Starting from the hybrid organic-inorganic perovskites (HOIPs), the introduction of a chiral molecule as organic cation leads to the breaking of the spatial inversion symmetry providing novel design tools by combining polarity and chirality [1,3]. This in turn open the way to explore several appealing chiroptoelectronic properties such as circular dichroism, circularly polarized emission, chiral-induced spin selectivity and so on. To extend the actual knowledge of these chiral systems and being able to properly engineer optimized phases it is important to carefully investigate the parameters affecting the chiral-induced response. From a materials chemistry point of view, this implies the ability of properties tuning by cation(s) and halide modulation/substitution. In this contribution we will present the results of the investigation of the role of the central metal and chiral cation, showing the modulation of the optoelectronic properties in two different approaches. On one side, we explored the preparation of a series of novel chiral metal halides including the same chiral cation, namely (4-Chlorophenyl)ethylenimine (Cl-MBA), but with a different central metal, namely Pb, Sn and Ge. This led to the discovery of the (R/S/rac-ClMBA)2SnI4 [4] and (R/S/rac-ClMBA)2GeI4 compositions showing also another structural 1D topology in presence of Ge, namely (R/S/rac-ClMBA)3GeI5 [5]. A comparison between these systems in terms of crystal structure and optical properties, coupled to computational modelling, sheds light on the tuning effect of central metal on the chiroptical properties. Another approach explore, relies on the properties modulation by including ad hoc synthesized bifunctional non-commercial chiral cations such as ((R)-1-amminobutan-2-ol) [6], thus exploring the impact of amine chemistry on the structural and optical properties. Final aim is to understand the impact of chemical degrees of freedom on the chirality transfer between the organic cation and the inorganic framework in order to provide tuning strategies for materials engineering.